The form factor you are talking about, is the 2.5" drive. A 2.5"
drive generally uses a max of 5V @ 1A or 5 watts. By using two
USB cables, each offering 5V @ 0.5A, you get enough power to run
a 2.5" drive. (7200RPM 3.5" drives use maybe 13W at idle, which
is why they are not good candidates for USB bus power. 2.5" or
smaller is where the fun begins.)
Checking the drives on the Seagate site, their largest 2.5" drive
is 160GB. WD offers 160GB as well. Hitachi is 160GB. Checking the
Toshiba site, the largest is a 200GB drive. You can get more info
on Toshiba drives here:
